Re: [閒聊] 每日leetcode

[SecondRun (南爹摳打)]

846. Hand of Straights

給定一整數陣列和分組大小
回傳可否把數字分組，每一組的數字要連續

Example 1:
Input: hand = [1,2,3,6,2,3,4,7,8], groupSize = 3
Output: true
Explanation: Alice's hand can be rearranged as [1,2,3],[2,3,4],[6,7,8]

Example 2:
Input: hand = [1,2,3,4,5], groupSize = 4
Output: false
Explanation: Alice's hand can not be rearranged into groups of 4.

思路:
先把數字出現次數記起來
找出一組裡最小的數字
把後面幾組都扣掉同樣次數，扣失敗就return false

C# code:
public class Solution
{
    public bool IsNStraightHand(int[] hand, int groupSize)
    {
        if (hand.Length % groupSize != 0) return false;
        var dict = new Dictionary<int, int>();
        foreach (int key in hand)
        {
            if (dict.ContainsKey(key)) dict[key]++;
            else dict[key] = 1;
        }
        var keys = dict.Keys.ToList();
        keys.Sort();
        foreach (int start in keys)
        {
            if (dict.TryGetValue(start, out int count) == false) continue;
            for (int i = 0; i < groupSize; i++)
            {
                int key = start + i;
                if (dict.ContainsKey(key) == false) return false;
                dict[key] -= count;
                if (dict[key] < 0) return false;
                if (dict[key] == 0)
                {
                    dict.Remove(key);
                }
            }
        }
        return true;
    }
}

--
(づ′・ω・）づ

--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 60.248.96.37 (臺灣)
※ 文章網址: https://www.ptt.cc/bbs/Marginalman/M.1717638646.A.0DA.html
※ 編輯: SecondRun (60.248.96.37 臺灣), 06/06/2024 09:52:11
推 JIWP: 大師
推 DJYOSHITAKA: 別捲了
推 deatheo: 大師